Journal article
Numerical investigation of the spatial scale and time dependency of tile drainage contribution to stream flow
Journal of hydrology (Amsterdam), Vol.538, pp.651-666
07/2016
DOI: 10.1016/j.jhydrol.2016.04.055
Abstract
•Tile drainage systems simulated though equivalent medium.•Equivalent medium parameters estimated though numerical experimentation.•Tile drainage contribution varied predictably with precipitation and spatial scale.•Basin shape, topography, precipitation, and antecedent moisture influenced tile response.
Tile drainage systems are pervasive in the Central U.S., significantly altering the hydrologic system. The purpose of this study was to assess the effects of tile drainage systems on streamflow. A physically based coupled hydrologic model was applied to a 45km2 agricultural Iowa watershed. Tile drainage was incorporated though an equivalent porous medium approach, calibrated though numerical experimentation. Experimental results indicated that a significant increase in hydraulic conductivity of the equivalent medium layer was needed to achieve agreement in total outflow with an explicit numerical representation of a tiled system. Watershed scale analysis derived the tile drainage contribution to stream flow (QT/Q) from a numerical tracer driven analysis of instream surface water. During precipitation events tile drainage represented 30% of stream flow, whereas during intervals between precipitations events, 61% of stream flow originated from the tile system. A division of event and non-event periods produced strong correlations between QT/Q and drainage area, positive for events, and negative for non-events. The addition of precipitation into the system acted to saturate near surface soils, increase lateral soil water movement, and dilute the relatively stable instream tile flow. Increased intensity precipitation translated the QT/Q relationship downward in a consistent manner. In non-event durations, flat upland areas contributed large contributions of tile flow, diluted by larger groundwater (non-tile) contribution to stream flow in the downstream steeper portion of the watershed. Study results provide new insights on the spatiotemporal response of tile drainage to precipitation and contributions of tile drainage to streamflow at a watershed scale, with results having important implications for nitrate transport.
Details
- Title: Subtitle
- Numerical investigation of the spatial scale and time dependency of tile drainage contribution to stream flow
- Creators
- Nicholas W Thomas - University of IowaAntonio A Arenas - University of IowaKeith E Schilling - University of IowaLarry J Weber - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of hydrology (Amsterdam), Vol.538, pp.651-666
- Publisher
- Elsevier B.V
- DOI
- 10.1016/j.jhydrol.2016.04.055
- ISSN
- 0022-1694
- eISSN
- 1879-2707
- Grant note
- name: Iowa Flood Center (IFC) at the University of Iowa; name: Iowa Watersheds Project
- Language
- English
- Date published
- 07/2016
- Academic Unit
- Earth and Environmental Sciences; Civil and Environmental Engineering; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984197425402771
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